A Phase IIb Study to Evaluate a Long-Acting Intramuscular Regimen for Maintenance of Virologic Suppression (Following Induction With an Oral Regimen of GSK1265744 and Abacavir/Lamivudine) in Human Immunodeficiency Virus Type 1 (HIV-1) Infected, Antiretroviral Therapy-Naive Adult Subjects

A Phase IIb Study Evaluating a Long-Acting Intramuscular Regimen of GSK1265744 Plus TMC278 For The Maintenance of Virologic Suppression Following an Induction of Virologic Suppression on an Oral Regimen of GSK1265744 Plus Abacavir/Lamivudine in HIV-1 Infected, Antiretroviral Therapy-Naive Adult Subjects

This study is a Phase IIb, randomized, multicentre, parallel group, open-label, study having an overall objective to evaluate the antiviral activity, tolerability, and safety of two intramuscular (IM) dosing regimens of GSK744 LA plus TMC278 LA, relative to GSK744 30 milligram (mg) plus Abacavir/Lamivudine (ABC/3TC) given orally once daily (QD), in HIV-1 infected antiretroviral-naïve subjects. GSK744 is the oral formulation of GSK1265744 (cabotegravir), GSK744 LA is the long acting injectable formulation of GSK1265744 and TMC278 LA is the long acting injectable formulation of TMC278.

The study will consist of three parts: an Induction Period, Maintenance Period and Extension Period. There is also a Long-Term Follow Up Period for subjects who withdraw from the study and have received at least one dose of GSK744 LA and / or TMC278 LA. In the Induction Period, eligible subjects will receive a combination of an oral regimen of 30 mg of GSK744 and 600/300 mg of ABC/3TC, once daily for 20 weeks. In the Maintenance Period, eligible subjects will be randomized 2:2:1 at Day 1 to receive an IM regimen of GSK744 LA 400 mg + TMC278 LA 600 mg every 4 weeks for 96 weeks (Q4W), an IM regimen of GSK744 LA 600 mg + TMC278 LA 900 mg every 8 weeks for 96 weeks (Q8W), or to continue on the oral Induction Period regimen of GSK744 30 mg + ABC/3TC once daily for 96 weeks (or 104 weeks if continuing on to the Extension Period). The Extension Period will allow for a collection of longer term efficacy and safety and tolerability data from subjects receiving GSK744 LA and TMC278 LA.

The study will involve sufficient subjects at screening in order to ensure a total of approximately 265 subjects at the beginning of the Induction Period and approximately 225 subjects randomized into the Maintenance Period.

Inclusion Criteria:

• Subjects screened for this study must be HIV-1 infected and >=18 years of age.
• A female subject is eligible to enter and participate in the study if she: is of non-child-bearing potential defined as either post-menopausal (12 months of spontaneous amenorrhea and >=45 years of age) or physically incapable of becoming pregnant with documented tubal ligation, hysterectomy or bilateral oophorectomy or; is of child-bearing potential with a negative pregnancy test at both Screening and first day of the Induction Period and agrees to use one of the following methods of contraception to avoid pregnancy 2 weeks prior to administration of IP, throughout the study, and for at least 2 weeks after discontinuation of all oral study medications and for at least 52 weeks after discontinuation of GSK744 LA and TMC278 LA: Complete abstinence from intercourse (where this is the subject's preferred and usual lifestyle); double barrier method (male condom/spermicide, male condom/diaphragm, diaphragm/spermicide); approved hormonal contraception; any intrauterine device (IUD) with published data showing that the expected failure rate is <1% per year; male partner sterilization prior to the female subject's entry into the study, and this male is the sole partner for that subject; any other method with published data showing that the lowest expected failure rate is <1% per year; any contraception method must be used consistently and in accordance with the approved product label. All subjects participating in the study must follow safer sexual practices including the use of effective barrier methods (e.g. male condom/spermicide) to minimize risk of HIV transmission.
• HIV-1 infection as documented by Screening plasma HIV-1 RNA>=1000 c/mL.
• CD4+ cell count >=200 cells/mm^3 (or higher as local guidelines dictate).
• ART-naive defined as having no more than 10 days of prior therapy with any antiretroviral agent following a diagnosis of HIV-1 infection. Any previous exposure to an HIV integrase inhibitor or non-nucleoside reverse transcriptase inhibitor will be exclusionary.
• French subjects: In France, a subject will be eligible for inclusion in this study only if either affiliated to or a beneficiary of a social security category.

Exclusion Criteria:

• Women who are breastfeeding.
• Any evidence at screening of an active Center for Disease and Prevention Control (CDC) Category C disease, except cutaneous Kaposi's sarcoma not requiring systemic therapy.
• Subjects with known moderate to severe hepatic impairment.
• Any pre-existing physical or mental condition (including substance abuse disorder) which, in the opinion of the Investigator, may interfere with the subject's ability to comply with the dosing schedule and/or protocol evaluations or which may compromise the safety of the subject.
• Subject who, in the investigator's judgment, poses a significant suicide risk. Recent history of suicidal behavior and/or suicidal ideation may be considered as evidence of serious suicide risk.
• The subject has a tattoo or other dermatological condition overlying the gluteus region which may interfere with interpretation of injection site reactions.
• History of ongoing or clinically relevant hepatitis within the previous 6 months, including chronic Hepatitis B virus (HBV) infection (HBsAg positive). Asymptomatic individuals with chronic hepatitis C virus (HCV) infection will not be excluded, however Investigators must carefully assess if therapy specific for HCV infection is required; subjects who are anticipated to require such therapy during the randomized portion of the study must be excluded.
• History of liver cirrhosis with or without hepatitis viral co-infection.
• Ongoing or clinically relevant pancreatitis.
• History of the following cardiac diseases: myocardial infarction, congestive heart failure, documented hypertrophic cardiomyopathy, sustained ventricular tachycardia.
• Personal or known family history of prolonged QT syndrome.
• Any condition which, in the opinion of the Investigator, may interfere with the absorption, distribution, metabolism or excretion of the drug or render the subject unable to receive study medication.
• History or presence of allergy or intolerance to the study drugs or their components or drugs of their class. In addition, if heparin is used during PK sampling, subjects with a history of sensitivity to heparin or heparin-induced thrombocytopenia must not be enrolled.
• Current or anticipated need for chronic anti-coagulation.
• Any evidence of primary resistance based on the presence of any major resistance-associated mutation in the Screening result or, if known, any historical resistance test result.
• Any verified Grade 4 laboratory abnormality.
• Any acute laboratory abnormality at Screening, which, in the opinion of the Investigator, would preclude the subject's participation in the study of an investigational compound.
• Subject has estimated creatinine clearance <50 mL/min via Cockcroft-Gault method.
• Alanine aminotransferase (ALT) >=5 times Upper limit of normal (ULN). Subjects with ALT >2xULN but <5xULN may participate in the study, if in the opinion of the Investigator and GlaxoSmithKline (GSK) medical monitor the lab abnormality will not interfere with the study procedures or compromise subject safety.
• Alanine aminotransferase (ALT) >=3xULN and bilirubin >=1.5xULN (with >35% direct bilirubin).
• Any clinically significant finding on screening or Baseline electrocardiograph (ECG), specifically: Heart rate <45 and >100 beats per minute (bpm) (Males) and <50 and >100 bpm (Females) (100 to 110 bpm can be rechecked within 30 minutes to verify eligibility), QRS duration >120 milliseconds (msec), QTc interval (B or F) >450 msec; non-sustained (>=3 consecutive beats) or sustained ventricular tachycardia; sinus pauses >2.5 seconds; 2nd degree (Type II) or higher atrio-ventricular (AV) block; evidence of WPW (Wolff- Parkinson-White) syndrome (ventricular pre-excitation); pathologic Q waves defined as Q wave >40msec OR depth >0.4 mV; any significant arrhythmia (either on ECG or by history) which, in the opinion of the Investigator and GSK medical monitor, will interfere with the safety for the individual subject.
• Subjects who are human leukocyte antigen (HLA)-B*5701 positive and unable to use an alternative nucleoside reverse transcriptase inhibitor (NRTI) backbone (subjects who are HLA-B*5701 positive may be enrolled if they use an alternative NRTI backbone that does not contain abacavir).
• Exposure to an experimental drug and/or experimental vaccine within 28 days or 5 half-lives of the test agent, or twice the duration of the biological effect of the test agent, whichever is longer, prior to the first dose of IP.
• Treatment with any of the following agents within 28 days of Screening; radiation therapy, cytotoxic chemotherapeutic agents, tuberculosis therapy and Immunomodulators that alter immune responses (such as systemic corticosteroids, interleukins, or interferons)
• Treatment with an HIV-1 immunotherapeutic vaccine within 90 days of Screening.
• Treatment with any agent, except recognized ART as allowed above, with documented activity against HIV-1 within 28 days of the first dose of IP.